From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7394AC43381 for ; Tue, 19 Feb 2019 16:08:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3FBD62147A for ; Tue, 19 Feb 2019 16:08:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729080AbfBSQIq (ORCPT ); Tue, 19 Feb 2019 11:08:46 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:34062 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726546AbfBSQIq (ORCPT ); Tue, 19 Feb 2019 11:08:46 -0500 Received: from bigeasy by Galois.linutronix.de with local (Exim 4.80) (envelope-from ) id 1gw7wp-0001FM-2l; Tue, 19 Feb 2019 17:08:43 +0100 Date: Tue, 19 Feb 2019 17:08:43 +0100 From: Sebastian Andrzej Siewior To: linux-rt-users@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Steven Rostedt Subject: [PATCH RT 4/2] hrtimer: Don't lose state in cpu_chill() Message-ID: <20190219160842.qxpwicoa5tzq4njo@linutronix.de> References: <20190218163107.iwdpngwmbs6xyk7x@linutronix.de> <20190218163137.cmor4ek3odus5m6j@linutronix.de> <20190219160755.fn4c65ph4lzqflw2@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190219160755.fn4c65ph4lzqflw2@linutronix.de> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In cpu_chill() the state is set to TASK_UNINTERRUPTIBLE and a timer is programmed. On return the state is always TASK_RUNNING which means we lose the state if it was something other than RUNNING. Also set_current_state() sets ->task_state_change to within cpu_chill() which is not expected. Save the task state on entry and restore it on return. Simply set the state in order to avoid updating ->task_state_change. Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior --- kernel/time/hrtimer.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 851b2134e77f4..6f2736ec4b8ef 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -1902,15 +1902,18 @@ void cpu_chill(void) { ktime_t chill_time; unsigned int freeze_flag = current->flags & PF_NOFREEZE; + long saved_state; + saved_state = current->state; chill_time = ktime_set(0, NSEC_PER_MSEC); - set_current_state(TASK_UNINTERRUPTIBLE); + __set_current_state_no_track(TASK_UNINTERRUPTIBLE); current->flags |= PF_NOFREEZE; sleeping_lock_inc(); schedule_hrtimeout(&chill_time, HRTIMER_MODE_REL_HARD); sleeping_lock_dec(); if (!freeze_flag) current->flags &= ~PF_NOFREEZE; + __set_current_state_no_track(saved_state); } EXPORT_SYMBOL(cpu_chill); #endif -- 2.20.1